Pointer or cursor movement on a raster-scanned image, such as a television screen or a computer monitor, will appear smoothest when pointer position data is updated at a rate that is at least equal to a refresh rate of a television screen or a computer monitor. The refresh rate of such a video display device is typically approximately 70 Hz, or about every 14 milliseconds. This refresh rate is faster than prior art wireless pointing devices and, as a result, perceived cursor or pointer motion controlled by such wireless pointing devices is rather jerky if the cursor position is updated only every 2-3 display refreshes. This application refers to both pointers and cursors on a display. These terms are used generally to refer to a position indicated on a display, including, but not limited to, for example, a blinking underscore, an arrow or an icon.
A conventional wired pointing device, such as, for example, a wired computer mouse, typically sends 8 bits of data indicating a change in position of the computer mouse in a first direction, for example, a horizontal direction, and another 8 bits of data indicating a change in position of the pointing device in a second direction, for example, a vertical direction, every 8 milliseconds over a port, such as, for example, a universal serial bus (USB) port. This results in a maximum pointing device speed of approximately 39 inches per second (ips), assuming a resolution of 400 dots per inch (dpi).
A wireless pointing device may send pointer position data to a receiver about every 25 milliseconds. Typically, the receiver is connected to a USB port of a computer device, such as, for example, a personal computer. The polling rate of the USB port is typically about every 8 milliseconds, or approximately three times faster than the rate at which pointer data is sent to the receiver from the wireless pointing device. Thus, typically, the receiver would provide one report through the USB port with updated pointer position data followed by two reports over the USB port with position data that is not updated. Because the pointer position is updated at a rate that is somewhat slower than the monitor refresh rate, the pointer or cursor movement using a conventional wireless pointing device may appear somewhat jerky. Further, assuming that the pointer position data is updated about every 25 milliseconds, resolution of the display is 400 dpi (0.0025 inches between pixels, and the maximum 8 bit signed value to be reported as cursor movement is 127, representing movement of 127 dots (127×0.0025 inches=0.3175 inches), then one can see that in a one second time period, about 40 reports having a maximum value of 127 may be reported, representing a maximum movement of 40×0.3175 inches, or 12.7 inches. Thus, when using a conventional wireless pointing device, cursor movement will be limited to about 12.7 inches per second.